For both environmental and energy conservation reasons, auxiliary DC battery power systems are beginning to be widely used in not only commercial applications, such as telecommunication network systems, but residential applications, as well. The battery power systems may be used to provide temporary power when the main power source, typically AC power goes out. In addition, these systems are often used in conjunction with other alternative power sources, such as solar and wind turbines that can be used to re-charge the battery systems. Many of these battery systems rely on circuit breakers in the battery circuit to serve to protect and electrically isolate a string of batteries. For multi-string battery plants, the trend is to provide a disconnect circuit breaker for each battery string, rather than using a common circuit breaker for the entire battery bank. Individual circuit breakers help isolate the faulty string.
In such systems, each battery string is provided with a separate disconnect circuit breaker, which serves to isolate the faulty battery string during overcurrent conditions and prevents problems in the string from affecting the other strings, chargers, circuit cables, and connected DC load. Thus, in such applications, the circuit breaker protects the system from overcurrent conditions.